Poor service

I phoned into FNB to dispute a debit order 5 times I spoke to 5 agents and every time they put me through to the part where u have to put in ur card number and pin when I have to speak to the agent again I can't hear a word, where my signal is perfect but they still cant hear me. 2 agents put down the call and the last Agent I spoke to didn't even listen to my complaint she just put the phone down in my ear. I'm sorry but its enough to make me cancel my banking with FNB I don't have exactly 27 min to waste on just disputing a debit order neither the airtime and still not be assisted.